* (except if `keepTogether` is enabled)\n     */\n    boundariesElement: 'viewport',\n    /**\n     * @prop {Boolean} flipVariations=false\n     * The popper will switch placement variation between `-start` and `-end` when\n     * the reference element overlaps its boundaries.\n     *\n     * The original placement should have a set variation.\n     */\n    flipVariations: false,\n    /**\n     * @prop {Boolean} flipVariationsByContent=false\n     * The popper will switch placement variation...